Survival of molecular gas in cavities of transition disks - I. CO
TLDR
In this paper, a new series of models were developed to simulate the physical conditions and chemical abundances of the gas in cavities to address the question whether the gas is primarily atomic or molecular inside the dust free cavities exposed to intense UV radiation.Abstract:
Context. Planet formation is closely related to the structure and dispersal of protoplanetary disks. A certain class of disks, called transition disks, exhibit cavities in dust images at scales of up to a few 10s of AU. The formation mechanism of the cavities is still unclear. The gas content of such cavities can be spatially resolved for the first time using the Atacama Large Millimeter/submillimeter Array (ALMA).Aims. We develop a new series of models to simulate the physical conditions and chemical abundances of the gas in cavities to address the question whether the gas is primarily atomic or molecular inside the dust free cavities exposed to intense UV radiation. Molecular/atomic line emission by carbon monoxide (CO), its isotopologues (13 CO, C18 O, C17 O, and 13 C18 O) and related species ([C i], [C ii], and [O i]) is predicted for comparison with ALMA and the Herschel Space Observatory.Methods. We use a thermo-chemical model, which calculates the radiative transfer both in lines and the continuum, and solves for the chemical abundances and gas temperature. The model is based on our previous work, but includes several improvements. We study the dependence of CO abundances and lines on several parameters such as gas mass in the cavity, disk mass and luminosity of the star.Results. The gas can remain in molecular form down to very low amounts of gas in the cavity (~1% of M Earth ). Shielding of the stellar radiation by a dusty inner disk (“pre-transition disk”) allows CO to survive down to lower gas masses in the cavity. The column densities of H2 and CO in the cavity scale almost linearly with the amount of gas in the cavity down to the mass where photodissociation becomes important. The main parameter for the CO emission from cavity is the gas mass. Other parameters such as the outer disk mass, bolometric luminosity, shape of the stellar spectrum or PAH abundance are less important. Since the CO pure rotational lines readily become optically thick, the CO isotopologues need to be observed in order to quantitatively determine the amount of gas in the cavity. Determining gas masses in the cavity from atomic lines ([C i], [C ii], and [O i]) is challenging.Conclusions. A wide range of gas masses in the cavity of transition disks (~4 orders of magnitude) can be probed using combined observations of CO isotopologue lines with ALMA. Measuring the gas mass in the cavity will ultimately help to distinguish between different cavity formation theories.read more
Citations
More filters
Journal ArticleDOI
ALMA Survey of Lupus Protoplanetary Disks. I. Dust and Gas Masses
Megan Ansdell,Jonathan Williams,N. van der Marel,John M. Carpenter,G. Guidi,Michiel R. Hogerheijde,G. S. Mathews,Carlo F. Manara,Anna Miotello,A. Natta,A. Natta,Isa Oliveira,Marco Tazzari,Leonardo Testi,Leonardo Testi,E. F. van Dishoeck,S. E. van Terwisga +16 more
TL;DR: In this paper, the Atacama Large Millimeter/Submillimeter Array (ALMA) was used to survey 89 protoplanetary disks around stars with M∗ > 0.1 M in the young (1-3 Myr), nearby (150-200 pc) Lupus complex.
Journal ArticleDOI
Structure of Stationary Photodissociation Fronts
Bruce T. Draine,Frank Bertoldi +1 more
TL;DR: In this article, a multiline UV pumping model was proposed to compare the effect of self-shielding on the overall fluorescent efficiency of the photodissociation front, including the effects of line overlap.
Journal ArticleDOI
ALMA Survey of Lupus Protoplanetary Disks I: Dust and Gas Masses
Megan Ansdell,Jonathan Williams,Nienke van der Marel,John M. Carpenter,G. Guidi,Michiel R. Hogerheijde,Geoff S. Mathews,Carlo F. Manara,Anna Miotello,Antonella Natta,Isa Oliveira,Marco Tazzari,Leonardo Testi,Ewine F. van Dishoeck,Sierk van Terwisga +14 more
TL;DR: The first high-resolution sub-mm survey of both dust and gas for a large population of protoplanetary disks is presented in this article, where the authors use ALMA to survey 89 disks around stars with a few Martian masses (0.2--0.4~$M_{\oplus}$).
Journal ArticleDOI
ALMA Survey of Lupus Protoplanetary Disks II: Gas Disk Radii
Megan Ansdell,Jonathan P. Williams,L. Trapman,S. E. van Terwisga,Stefano Facchini,Carlo F. Manara,N. van der Marel,Anna Miotello,Marco Tazzari,Michiel R. Hogerheijde,G. Guidi,Leonardo Testi,E. F. van Dishoeck +12 more
TL;DR: In this article, the Atacama Large Millimeter/Sub-Millimeter Array (ALMA) Band 6 observations of a complete sample of protoplanetary disks in the young (~1-3 Myr) Lupus star-forming region, covering the 1.33 mm continuum and the 12CO, 13CO and C18O J = 2-1 lines.
Journal ArticleDOI
Large-scale asymmetries in the transitional disks of sao 206462 and sr 21
TL;DR: In this paper, the Atacama Large Millimeter/submillimeter Array (ALMA) observations in the dust continuum (690 GHz, 0.45 mm) and 6-5 spectral line emission of the transitional disks surrounding the stars SAO 206462 and SR 21 were presented.
References
More filters
Journal ArticleDOI
Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
Göran Pilbratt,J. R. Riedinger,T. Passvogel,G. Crone,D. Doyle,U. Gageur,Ana M. Heras,C. Jewell,L. Metcalfe,S. Ott,Michael Schmidt +10 more
TL;DR: Herschel was launched on 14 May 2009, and is now an operational ESA space observatory o ering unprecedented observational capabilities in the far-infrared and sub-millimetre spectral range 55 671 m.
Journal ArticleDOI
Dust Grain-Size Distributions and Extinction in the Milky Way, Large Magellanic Cloud, and Small Magellanic Cloud
TL;DR: In this paper, the authors construct size distributions for carbonaceous and silicate grain populations in different regions of the Milky Way, LMC, and SMC, and adopt a fairly simple functional form for the size distribution, characterized by several parameters.
Journal ArticleDOI
The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
Albrecht Poglitsch,C. Waelkens,Norbert Geis,Helmut Feuchtgruber,B. Vandenbussche,L. Rodriguez,Oliver Krause,Etienne Renotte,C. Van Hoof,P. Saraceno,J. Cepa,Franz Kerschbaum,P. Agnese,Babar Ali,Bruno Altieri,Paola Andreani,J.-L. Augueres,Zoltan Balog,L. Barl,Otto H. Bauer,N. Belbachir,M. Benedettini,N. Billot,O. Boulade,Horst Bischof,Joris Blommaert,E. Callut,C. Cara,R. Cerulli,D. Cesarsky,Alessandra Contursi,Ybe Creten,W. De Meester,V. Doublier,E. Doumayrou,L. Duband,Katrina Exter,Reinhard Genzel,Jean-Marie Gillis,Ulrich Grözinger,Thomas Henning,J. M. Herreros,Rik Huygen,Massimo Inguscio,Gerhard Jakob,Claude Jamar,C. Jean,J. de Jong,Reinhard O. Katterloher,Csaba Kiss,Ulrich Klaas,Dietrich Lemke,Dieter Lutz,Suzanne C. Madden,Benoit Marquet,J. Martignac,A. Mazy,Patrick Merken,Francis Montfort,L. Morbidelli,Thomas Müller,Markus Nielbock,K. Okumura,R. Orfei,Roland Ottensamer,Roland Ottensamer,Stefano Pezzuto,Paola Popesso,Jan Putzeys,S. Regibo,V. Reveret,Pierre Royer,Marc Sauvage,Jürgen Schreiber,Jutta Stegmaier,D. Schmitt,J. Schubert,E. Sturm,M. Thiel,G. Tofani,R. Vavrek,M. Wetzstein,E. Wieprecht,Erich Wiezorrek +83 more
TL;DR: The Photodetector Array Camera and Spectrometer (PACS) as discussed by the authors is one of the three science instruments on ESA's far infrared and sub-mil- limetre observatory.
Journal ArticleDOI
The Evolution of viscous discs and the origin of the nebular variables.
Donald Lynden-Bell,J. E. Pringle +1 more
Journal ArticleDOI
Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
TL;DR: In this paper, the authors construct size distributions for carbonaceous and silicate grain populations in different regions of the Milky Way, LMC, and SMC, and adopt a fairly simple functional form for the size distribution, characterized by several parameters.